Deathwatch: Underkill
by Tomoyuki Tanaka
Summary: When the superhuman Space Marines of the revered Deathwatch chapter succumbs to the insidious claws of a Genestealer Cult, it is up to the brave men of the Imperial Guard to step up and cleanse the galaxy of Xenos scum!
"This mine is mine!"

As the former lord of House Chevron bolted toward Lieutenant Ikeda Iemitsu, the latter put a bolt round in his skull.

"No, this mine is the Emperor's." Ikeda lowered his smoking bolt pistol as he watched the now-prone body of the disgraced noble. House Chevron had been the dominant guild governing Phantos Sextet for so long that nobody had doubted their loyalty, and they had exploited that trust to their own benefit, turning their backs on the light of the Emperor and throwing their ilk with the hated xenos scum. Noticing his men forming up around him, Ikeda tried to think of something more inspiring, but could only come up with a lame "uh...death to all heretics?"

"You've got to be more convincing than that, sir," Mitsuhide chuckled as he scanned the now-still mines with his hot-shot lasgun. The burly man was on point, his senses widely recognized to be the keenest among the platoon. "Anyway, the area's clear."

Ikeda glanced at the torn bodies of the noble and his personal guard that had been serving as their escorts until the sudden, surprising betrayal. No doubt these heretics had been leading them into an isolated terrain that would be to their advantage, waiting to spring their trap as they abruptly ambush his soldiers, catching them off guard with a few well-placed rounds from their autoguns.

It would have succeeded, if not for one thing.

Ikeda's platoon of soldiers were just any ordinary Imperial Guardsmen. They were storm troopers, elite and highly trained soldiers who had experienced countless bitter battles and betrayals yet surviving to this day. It was testament to their discipline and skill that none of his soldiers lay among the dead. Matsuda caught a round in his shoulder, but his carapace armor had protected him from the worst of the shot. Nothing to inhibit him from fighting.

It took under a minute for the elite Kamikaze Troopers of the Draconian Armored Defense Force to dispatch Lord Chevron and his twelve bodyguards their barrage of hot-shot lasgun fire burning into their vitals with deadly precision.

"Now that our escorts are dead, what do we do?"

Sato raised a hand and asked while shifting his bulky backpack to ease the weight off his shoulders. The backpack might provide more punch to their lasgun fire and supply them with a lot more ammunition than a typical lasgun issued to the normal Guardsmen, but it was cumbersome and heavy. Still, the storm troopers put up with it because the additional firepower and ammunition was often worth the burden.

"We continue on. Inquisitor Chogryn has ordered us to investigate an anomalous reading in the mine's lower levels."

"Yeah, but all communication has been severed," Takeda reported as he slapped the receiver of his vox-caster in hopes of regaining a signal. Nothing but static hissed from the machine. Frustrated, he struck the bulky backpack, only to have the same results. "I can't transmit or receive any messages from the surface."

"I guess we all know the cause of the anomalous reading, huh?" Mitsuhide muttered dryly. "Anyway, heads up. I'm detecting movement ahead."

"All right, stay frosty, people." Lieutenant Ikeda strode briskly to the front, his bolt pistol heaved up and aimed at the shadows. "We don't know how many more of these heretics might be hiding in here. Plus we need more intel than this. Until we get something useful, we will not be aborting the mission."

"So another suicide mission, huh? What else is new?"

"Shut it, Matsuda," Mitsuhide growled as he aimed and took a shot, the ruby red las-fire from his weapon eliciting a howl from the shadows. Something clattered on the ground...a dismembered limb holding onto a miner's power tool. "Emperor's Throne...is that what I think it is?"

Amplifying his vision through the use of special storm trooper-issue goggles, Ikeda could understand Mitsuhide's concern. The limb that had dropped onto the ground looked like some grotesque parody of a human's, the flesh purplish and abnormally muscular. Even though the fingers wrapped around the handle of a power hammer was unmistakably human, long, sharp claws seemed to snake from their tips.

"Genestealer hybrids."

Sato's hushed whisper was enough for the other storm troopers to tense up. Spreading out, the Kamikaze Troopers relied on their acute senses, honed instinct and superior technology to keep track of their enemies' presence, firing whenever they detected so much as a breeze from the shadows. Occasionally screeches of pain erupted, and ichor was spilled, and an impressive shot from Mitshude actually punched cleanly through a huge and clumsy miner, vaporizing his brains inside his skull.

"Third generation hybrid."

Ikeda noted as he scrutinized the corpse while keeping one eye on the shadows. The features were all there - while the miner could pass off as human, his incredibly muscular stature and slightly deformed features marked him as distinct from a normal human. The claws and forked tongue, while not as obvious as a first or second-generation hybrid, was still present somewhat in a more faded manner.

As he did so, he was forced to dodge a crude projectile from a nailgun or some sort of mining tool. Rolling on the ground, he glanced up at the direction where the high-speed bolt had come from. Firing more from reflex than anger, he heard a curse as the bolt round lodged itself into his assailant.

"The mines are infested!"

"Flamer, front!"

"Got it, sir!"

Kaen stepped forward and unleashed a brilliant gout of flames that washed over the shadows, incinerating an unfortunate group of hybrids that had stupidly chosen to bunch up. No doubt the shooter who had aimed for Ikeda was among them, screaming in both rage and pain as the burning promethium consumed him. There was a mild explosion as the intense heat cooked off the power tool, causing it to blow up in the inferno.

Cries of outrage and vengeance echoed throughout the mine, and for one moment it sounded like thousands of... _things_ scuttling across the vast shafts, all converging upon the Kamikaze Troopers' position.

"Sir, we're surrounded."

Even the usually calm Mitushide's voice was tense as he unleashed a barrage of hot-shot ruby-red las-fire into the encroaching horde. Ikeda understood his despair. The storm troopers had to move, or they would be surrounded and hemmed in by an overwhelming tide of unspeakable horrors, cornered and slaughtered to a man by sheer numbers.

"Move!"

Ikeda tapped his helmet in hopes of getting a display of the mine's outlay through his ocular augmetics. If he could just find a favorable terrain where they could barricade themselves, they might be able to endure the siege the miners were throwing at them...

"Purestrain genestealer!"

Tanaka yelled out a warning as he hefted his hot-shot volley gun up and took aim at the ceiling. Three, no, four purestrain genestealers were scrabbling toward them as they hissed, their rending claws wickedly stabbing into the ceramite, tearing through the rock-hard material with terrifying ease. A high-pitched whine burst through the mines as Tanaka unloaded a volley of high-powered las-fire into the approaching xenos, dropping them before they could reach their position.

Ikeda silently praised the hot-shot volley gunner for his foresight. If the purestrain genestealers had successfully landed into their midst, there was no doubt the human storm troopers would be utterly torn apart by the deadly aliens.

"Move, move, move! Kaen, lay down a suppressing fire and cover our retreat!"

"You got it, sir!"

Kaen took up the rear, his flamer roaring as he sprayed another stream of blazing promethium into the mass of deformed miners crawling upon them. Inhuman screams wailed across the caverns as the hybrids were cooked by the superheated flames. The terrain they thought was to their advantage now proved to be a deathtrap for them, enclosing them in a confined space that provided little in the way of evasion and escape.

The storm troopers hurried onward, dropping more miners with hot-shot las-fire as they ran with their commander. Ikeda had located a sector that seemed secured, with walls to their back and sides. Dodging a projectile from another crudely repurposed mining tool, he skidded across the dusty surface and thumped into cover. Springing back into action almost immediately, he fired with his bolt pistol to cover his retreating man.

Kaen continued to lay down gouts of suppressing fire to torch pursuing miners, hybrids and genestealers, but Ikeda was worried about his rate of consumption.

"Kaen, make sure you save some ammo for the trip back. Get to cover."

"Yes, sir."

Kaen obediently dropped under another cover. As the storm troopers settled down, Mitsuhide threw a melta bomb right at the ceiling. A purestrain genestealer hissed as it scrambled right over the explosive, only for it to go off at the moment of contact.

The effect was tremendous.

The purestrain genestealer vanished instantly, nothing left of it but vaporized blood and flesh, as the melta bomb went off, blowing up the ceiling and caving in the only entrance. The miners and hybrids tried to halt their advance and fall back, and those too slow were caught by the explosion. Those who survive the thermal energy and shockwaves were then buried by falling debris

"Well, we sure caught ourselves a breather." Mistuhide's face was masked by the standard Miltarum Tempestus helmet, but Ikeda was sure he was grinning broadly underneath. "That ought to hold them off for a while."

"Uh, I don't want to rain on your parade, man, but didn't you just blow up our only route of escape?"

"What are you talking about, Sato? You saw that mass of miners, didn't you? There's no escaping that way."

Ikeda sighed. "As much as I hate to admit it, Mitsuhide is right. Unless we have enough firepower and ammo to tear through that volume of heretics and xenos, there's no way we can go that way."

"Damn. What do we do now?"

"Well, I'm sure we'll be able to locate an alternative escape route somewhere..."

"Yeah? If there is one, how do we know the miners won't find it before we do, and sneak up on us?"

The Kamikaze Troopers looked at each other grimly, their desperate situation finally sinking down on them. Matsuda had a point. Even if they did find an escape route, it was unlikely they would find it before the miners, who were much more familiar with the terrain that was basically their home turf. As Ikeda racked his brains to think of a solution, he was saved by the hesitant voice of Tanaka.

"Uh, sir, I think you should see this."

Ikeda strode over, partially relieved to be dragged away from the urgent matter at hand. As he approached Tanaka's position, he could see why the hot-shot volley gunner was so tense.

It was a Space Marine. Or to be more accurate, a dead Space Marine.

And he was not alone.

At least three superhuman soldiers of the Adeptus Astartes lay immobile in the sector the Militarum Tempestus Scions found themselves in, their black armor broken and ripped apart by inhuman claws. Slumped or fallen, their torn and bloodied bodies showed no sign of life. Yet the recently dried blood, as indicated by the readers on the storm trooper's standard-issue occular equipment, showed that it wasn't long since they had fallen. A few weeks at the most.

"What are the Space Marines doing here?" Matsuda demanded as he crawled over, his voice gripped in awe. Ikeda was similarly amazed. Mortal men, even storm troopers of their caliber, rarely had the chance to see these revered angels of death in the flesh.

"Uh, that black armor and symbols...aren't these Space Marines from the Deathwatch chapter?" Kaen asked, unable to keep a tremor out of his voice.

"It's all falling into place now."

"Sir?"

Mitsuhide glanced at Ikeda, who was mumbling to himself. Ikeda paused as he tried to digest the situation, and shook his head. Taking a deep breath, he looked at all his men.

"I guess there's no point keeping things from you guys any further. Inquisitor Chogryn actually wanted me to stay silent on this, but as things are, it's better if I brief you on what I know."

The rest of the storm troopers exchanged glances. It was normal for the Inquisitor, and sometimes their commanding officer, to withhold information from the rank-and-file men. For the ruinous powers, or nefarious agents of vile xenos had ways to extract information from soldiers that would prove valuable enough to change the tide of war. Plus they had supposedly being indoctrinated from young to follow orders without questioning, and took their officer's lack of detail as a given.

"A week ago, Inquisitor Chogryn received a distress signal from here, Phantos Sextent. Apparently a Deathwatch Kill Team had been dispatched here to root out a reported genestealer infestation."

"And we were not informed of this genestealer infestation until now?"

"Well, yeah...apparently Inquisitor Chogryn thought it was limited to the lower levels of the mines," Ikeda explained to an annoyed Matsuda. "We never imagined it to be on such a large scale, or that there were already generations of Genestealer Cultists. The Deathwatch Kill Team went in on the assumption that it was a fresh invasion, where the genestealers had yet to taken root in the population."

"And that Kill Team got killed."

"So these are their remains," Sato added to Tanaka's dry remark. "I guess even the honorable Space Marines will fall to overwhelming numbers. But aren't the Deathwatch supposed to specialize in exterminating xenos?"

"Yeah, it looks like the Deathwatch Kill Team watched the deaths of each other." Tanaka chuckled at his own gallows humor.

"Is this Kill Team Cassius?" Mitsuhide asked as he studied the markings and symbols painted on the shoulder pads of the dead Space Marines. "If I recall, Lord Cassius was due to arrive in this sector..."

"Nah, they didn't send Kill Team Cassius for this mission," Ikeda waved his hand dismissively. "That would have been Overkill."

Everyone just stared at him.

"Anyway, we should find a way out of here...whoa!"

As Ikeda leaned against a wall, he almost fell over as the outcrop gave way. Stumbling, he glanced up in surprise as he saw an opening yawn through what used to be a wall.

"W...what's this?"

"It seems that you've unlocked a secret tunnel, sir," Mitsuhide said as he took point, pointing the barrel of his hot-shot lasgun into the darkness beyond. "Hmm, no signs of movement or the enemy. Looks clear."

"Seems like we've found our alternate escape route, eh?" Sato sounded immensely relieved. But Matsuda was quick to stamp on it.

"It could be a trap."

"Could be," Ikeda agreed. "But it's better than staying here to die. I say we move out."

The storm troopers concurred. A thorough check revealed that they still had quite a bit of ammunition, though Kaen's flamer was dangerously low on fuel - about less than half of his tank sloshed with the precious promethium.

"I'll cover you guys with my hot-shot volley gun once things get too hot."

"We're counting on you, hot-shot."

And so they moved. As they double-timed through the tunnel, Matsuda began grumbling.

"We should contact the rest of the regiment and purge this world as quickly as possible."

"Nah, we should leave it to other Imperial Guard regiments. Our regiment is an armored one, there's no way our tanks could crawl through the mines to flush out these xenos scum."

The Draconian Armored Defense Force was primarily an armored regiment from the agri-world of Draconis III, and the majority of what little infantry they had were intensely trained into storm troopers such as themselves. While the Draconian Armored Defense Force excelled in armored warfare and devastating large, open plains of enemies, their tanks, gunships and armored vehicles would prove of little use inside a confined space like these mines.

As they moved along the shadowy terrain, Mitsuhide halted at point, raising a hand to stop everyone.

"Movement."

And that word was accompanied by swarms of cultists. Appearing out of nowhere, they began dropping from the shadows and descending upon the hapless platoon of storm troopers, wielding everything from power axes to power picks, repurposed nailguns to autoguns. In addition to third and fourth generation hybrids, abnormally huge abhuman-like cultists emerged, dragging along the heavy and bulky power axes with little effort. The Kamikaze Troopers opened fire immediately, cutting down a large swathe of them, but they were unable to put a dent in the overwhelming numbers.

To make matters worse, a massive figure darted out of a crevice and hauled itself into the cavern, landing heavily on the rockcrete.

"T...that's...!"

A purestrain genestealer, or so Sato wanted to say, but the words died in his throat. For the monstrous creature before them was no ordinary purestrain genestealer. In fact, other than several physical resemblances, it probably wasn't just a genestealer. It was _massive_ , towering over the twin purestrain genestealers that were lurking close by like bodyguards, its multiple hands extending to display razor-sharp claws. Snarling, with a forked tongue darting out, the monstrosity lumbered toward the storm troopers, shrugging off the hail of hot-shot las-fire that pelted its large frame.

"What the hell is that thing?!" Matsuda screamed as he unleashed a hail of hot-shot rounds into the creature's face, with little effect. Ikeda swallowed, fighting back the cold fear that swam up his heart with steely discipline.

"A Patriarch. The Phantos Patriarch, no doubt. I bet these cultists around us worship him as the four-armed Emperor or something. He's usually the leader of these uprising, so if we kill him..."

"Easier said than done! That thing's just brushing off everything we throw at him!"

Even a plasma blast from Tachibana only seared off a segment of the thing's organic armor, but didn't slow it down. Tachibana gritted his teeth as he aimed his plasma gun again, blasting the monster with super-heated blub blobs of destructive energy. Indeed, it dealt much more damage than the ineffectual hot-shot las-fire that accompanied him, but it wasn't enough to slow the patriarch down.

Tanaka, on the other hand, was focusing on the cultists that threatened to swamp them with superior numbers. Laughing manically, he hosed down fifteen cultists on the way to the exit, his hot-shot volley gun wailing shrilly as it let loose volley after volley of high-powered ruby blasts. Thanks to him, the other storm troopers were able to make their escape, switching their attentions to the cultists rather than waste their shots on the monstrous Patriarch.

Wounded and smoking, the Patriarch determinedly closed in on them, a ghastly psychic shriek filling the space. Wincing, Ikeda bit down on his tongue and bellowed an order.

"Kamikaze Troopers! We're getting out of here!"

Making their way to the exit, the Kamikaze Troopers filed out in disciplined order, rushing out of the cavern in their respective squads as one covered the other. It wasn't long before they stepped out into open night air, stumbling into the vast, open world of Phantos Sextet.

But it wasn't over.

Even as the storm troopers put some distance between themselves and the mine entrance, the Patriarch burst out, screeching furiously as he doggedly pursued the elite human soldiers. Following behind him as if a dam had burst loose, a flood of cultists and hybrids swept out of the mine in blind pursuit, purestrain genestealers mixed into their numbers.

And then they exploded into blood and gore.

The Patriarch stopped for a moment, confused as his legions of troops vanished into blood and organic matter. Howling explosive rounds sailed through the air before descending in an arc and smashing into the milling hordes of cultists, obliterating them into bloody pastes from the sheer firepower.

The cavalry had arrived.

"Hell, yeah!"

Whooping, Sato and the rest cheered as the black tanks of the Draconian Armored Defense Force lumbered over. The Leman Russ Main Battle Tanks fired a synchronized volley of death, spitting out destruction with their high explosive rounds to devastate the cultists, while a squadron of Leman Russ Punishers disgorged their punishing rounds upon any who got too close to the armored line. As the purestrain genestealers tore away from the confused horde and rushed toward the tanks, another squadron of Leman Russ Executioners rolled up and executed them in blinding blobs of plasma.

The Patriarch hissed in fury. Braving the storm of destruction, he leaped over Punisher Gatling rounds and plasma bursts, seeking vengeance for his subordinates by tearing into the tanks' armored plating with his claws...

...only for an Imperial Knight to cleave him in half with his reaper chainsword. The Knight Paladin stomped on the fallen Patriarch ruthlessly, crushing the once-worshipped xenos into a bloody pulp before leveling his rapid-fire battle cannon at the ravaged hordes of cultists and opening fire.

With their Patriarch murdered in such a gruesome manner, the surviving cultists broke morale and began to fled, only to get in the way of each other and choked the mine entrance. This made them easy targets for the Leman Russ Punishers.

"Well," Ikeda remarked as he pulled off his helmet to wipe away his perspiration, beaming proudly at his storm troopers when he realized that they had not suffered even a single casualty. "Even without a Deathwatch Kill Team, I guess this still is Overkill."


End file.
